With regard to the prior art apparatuses in contrast to the Semiautonomous Flight Director (SFD) device disclosed herein which supplants pilot""s skill in flying an aircraft employing an autopilot; all of the prior art apparatuses require a skilled pilot""s knowledge and abilities for safe and/or effective operation of an aircraft employing an autopilot whether manned or unmanned. To one degree or another each prior art apparatus either augments, on a limited basis or assists on a limited basis, a skilled pilot""s direct operation of an aircraft""s flight controls or they afford a skilled pilot a means by which to better utilize an autopilot while in flight. However, none of the prior art apparatuses supplant""s the pilot""s skill in flying an aircraft whether manned or unmanned.
The primary departure, of the SFD, from the prior art is that the prior art requires that the pilot temporarily over ride or disconnect from the autopilot and take xe2x80x9cdirectxe2x80x9d control of an aircraft""s flight controls to make changes in the aircraft""s flight direction. The fields of aerospace and aviation teaches that such changes in an aircraft""s flight controls can only be made safely by a skilled pilot, skilled in flying the particular aircraft flown.
All of the prior art allows for direct control of an aircraft""s flight controls by a pilot whether or not the pilot employs an installed autopilot or not. The SFD on the other hand does not allow direct control of an aircraft""s flight controls in order to effect safe flight when the SFD is employed with an autopilot.
The SFD""s secondary departure from the prior art is that the prior art requires that the pilot temporarily disengage or over ride the autopilot to make changes in the aircraft""s flight controls in order to subsequently program or reprogram the autopilot whereas the SFD allows for continuous autopilot control of the aircraft while coincidentally allowing the pilot to make changes in direction or flight function.
The third and paramount departure from all the prior art devices is the manner by which the prior art effects the programming or reprogramming of an autopilot while in flight which requires the pilot to have the necessary skills in flying the particular aircraft flown in order to safely effect such programming or reprogramming of an autopilot whereas the SFD does not require such skills in order to safely program or reprogram an autopilot while in flight.
With regard to the prior art it is during the periods of time where the pilot overrides, disengages, or otherwise suspends the autopilot""s control over the aircraft that precludes the safe operation of an aircraft by an unskilled pilot or operator.
The prior art always employs a plurality of means to control an aircraft either by the direct control of the aircraft by a skilled pilot or the aircraft is controlled autonomously by the autopilot. The term xe2x80x9cSemiautonomousxe2x80x9d as applied in this application means that the aircraft is controlled singularly, at all times, by the autopilot; autonomously, but, re-programmable without temporarily suspending the autopilot""s control of the aircraft to make flight changes.
Flight control, situational awareness and the lack thereof for Unmanned Aerial Vehicle (UAV) pilots is of particular concern to UAV manufacturers and users alike. Most specifically military and non-military government users. As of the date of this application, over eighty-five percent of all UAVs currently being flown in the world today will crash as a result of a UAV pilot""s lack of situational awareness and the resulting loss of flight control over the UAV flown regardless of any given UAV pilot""s skill and/or experience level. These factors, according to current UAV mishap statistics, are of paramount importance to the Federal Aviation Agency (FAA) and the National Transportation and Safety Board with respect to their authorization for use and implementation of UAV technology in the civilian and commercial aviation sectors.
The SFD was specifically devised to address these issues of pilot situational awareness in UAV""s and more specifically the horizontal or vertical take off or landing (HOVTOL) UAV of U.S. Pat. No. 5,890,441 issued Apr. 6, 1999 to the applicant Terry J. James and Johnny Swinson (deceased; Suanne Walker, executrix). It is consequential that the SFD provides a means by which manned aircraft may be piloted by unskilled pilots or utilized by skilled pilots of manned aircraft to reduce cockpit workload as well as other UAV platforms.
Disclosed in U.S. Pat. No. 5,255,880 issued on Oct. 26, 1993, to Woon Lyloc and David C. Pattison, is a manual override apparatus which allows only a skilled pilot to safely override autopilot operation in aircraft that have fly by wire or fly by light flight control systems as opposed to mechanical flight control systems having an autopilot system.
In the prior art device of U.S. Pat. No. 5,255,880 a pilot does not have to disengage the autopilot in order for a skilled pilot to make direct changes to the flight controls of an aircraft employing the device. The degree and amount of linear change made by the action of a pilot displacing a given aircraft""s manual control stick or yoke is sensed by a circuit when the pilot places a specific amount of force on the control stick or yoke. Once the amount of force level in the pilot""s yoke or control stick reaches a certain threshold, the magnitude and degree of control stick deviation, and movement, in linear terms, of the pilots"" control stick or yoke movement effects a proportionate degree of change in the aircraft""s flight controls to the exact degree of deviation made in the pilot""s control stick or yoke as in normal flight.
It is important to note here, that in the application of U.S. Pat. No. 5,255,880, only a skilled pilot having the knowledge and sufficient specific skills in flying a particular aircraft under non-autopilot operation could safely make such linear deviations in the control stick or yoke of such an aircraft in order to avert directing the autopilot to initiate a negative or dangerous flight maneuver. The autopilot employing this device would only effect the changes initiated by the pilot to include negative and acrobatic maneuvers. The reason for this is that the amount of deviation made in the pilot""s control stick is directly related and linearly proportionate to the amount and degree of linear and proportional change effected in the flight controls of the particular aircraft flown by the pilot. If the pilot was unskilled in flying the aircraft a crash could occur as a result of placing too much or too little displacement in the control stick or yoke.
This is to say that, in the application of the prior art of U.S. Pat. No. 5,255,880, if an unskilled pilot were to place the control stick into a position and to such a degree that it would cause a negative or dangerous flight maneuver the flight controls of the aircraft flown under autopilot command employing the prior art would likewise place said aircraft in a negative or dangerous flight regime. This could result in the loss of aerodynamic control of the aircraft if it were not for the prior art""s requirement for a trained pilot""s skill being necessary in precluding the placing of the control stick in such a position as to cause a dangerous or negative flight regime. The prior art of U.S. Pat. No. 5,255,880, therefore, requires a skilled pilot in order to safely utilize the invention.
The advantage of U.S. Pat. No. 5,255,880 is it allows override control of the autopilot""s flight controls of an aircraft having a fly by wire or fly by light flight control system without disengaging the autopilot whereby a skilled pilot may make changes directly to the flight controls even when the autopilot is active.
A disadvantage of this prior art device is that it is not applicable to aircraft having flight control systems other than fly by light or fly by wire flight control systems and the system requires operation only by a skilled pilot while overriding an active autopilot.
U.S. Pat. No. 5,067,674 issued Nov. 26, 1991 to Albert Heyche, Alain Latteur, and Philippe Dekoninck, all of Brussels Belgium, discloses a control system for remote controlled aircraft. The device is, in effect, a compensator for variations of time lags associated with the difference in time from the moment a pilot initiates an action by remote control until the aircraft, in flight, actually begins to act on the change with respect to the aircraft""s resultant attitude change that follows the execution of the various interactions of the aircraft""s flight control surfaces.
It is further disclosed in U.S. Pat. No. 5,067,674 that the device automatically compensates for variations in normal operation of a flight control system of a remotely controlled helicopter to prevent a certain limited number of negative flight regimes.
The prior art device of U.S. Pat. No. 5,067,674 xe2x80x9caidsxe2x80x9d, in an automatic manner, a skilled RC pilot in piloting a remotely controlled helicopter. The system does not however, supplant the skill normally required to pilot a remotely controlled aircraft or helicopter.
U.S. Pat. No. 4,964,598 issued Oct. 23, 1990 to Zacharaia Berejik, Ramot Tzahala; Allon Wallach, Moshav Talmei Elazar, of Israel discloses an apparatus to automatically stabilize, to a certain degree, a remotely controlled aircraft in yaw and roll for aircraft turns initiated by a pilot when the aircraft is required to bank in order to accomplish a turn. The apparatus also provides automatic stabilization compensation of the pitch of a remotely controlled aircraft for aircraft ascensions and descentions initiated by the pilot.
The apparatus of U.S. Pat. No. 4,964,598 however, does not supplant pilot skill but, rather, is an aid to a skilled pilot by automatically compensating, to a certain degree, for a pilot""s lack of situational awareness of the difference between what a pilot perceives to be the actual attitude of a remotely controlled aircraft versus the actual physical attitude of the remotely controlled aircraft when performing flight maneuvers. The apparatus also holds the flight controls in the last commanded flight command in the event of interferences with the aircraft""s radio link in RC applications. The apparatus can not preclude a pilot""s placing the aircraft in a negative flight regime however.
The apparatus of U.S. Pat. No. 4,964,598 allows a skilled pilot to perform flight maneuvers, including negative flight regimes, in order to accomplish flight maneuvers in such a way as to compensate, to a limited degree, for the lack of the pilot""s situational awareness of the actual physical attitude of the remotely controlled aircraft with respect to the pilot""s perception of the aircraft""s attitude. The device is essentially stabilizes the flight control surfaces of an aircraft or helicopter. It does not however compensate for pilot skill in flying an aircraft or helicopter.
U.S. Pat. No. 4,642,774 issued Feb. 10, 1987 to John P. Centala and Kenneth W. McElreath of Iowa is similar in function to the apparatus earlier mentioned herein and which is disclosed in U.S. Pat. No. 5,255,880. Both inventions require a skilled pilot in order to effect the product of the inventions.
The apparatus of U.S. Pat. No. 4,642,774 allows only for a skilled pilot to safely make manual flight control deviations under autopilot control and then subsequently return to the autopilot""s preprogrammed flight regime, or optionally, to a new program set. The new program set however, is determined by the amount and degree of liner displacement made by the skilled pilot""s manual flight control deviations of the control stick or yolk.
The Centala device, when activated to disconnect from the autopilot, allows the pilot to fly the aircraft directly, as normal, as if the autopilot was not on in order to effect a new flight regime which could include a negative or dangerous flight regime if it were not for the pilot""s skill and knowledge.
The Centala device requires that only a skilled pilot could safely make the changes to the aircraft""s flight controls employing the device to effect safe flight changes in the autopilot""s flight regime. Any change in the controls made by the pilot will be effected by the autopilot whether such changes are acrobatic in nature, and /or safe or not.
The primary effect of the Centala prior art device is to allow for override changes in an autopilot""s control of an aircraft only by a skilled pilot""s degree of linear displacement of the pilot""s aircraft control stick by optionally either allowing the autopilot to return to its preprogrammed flight path or to an altered programmed flight path in accordance with the degree of linear displacement of the pilot""s aircraft control stick which could only be effected, safely, by a skilled pilot. The Centala device relinquishes direct control of the aircraft to the Pilot in order to effect autopilot changes.
All the actions of the Centala device are, therefore, accomplished by a skilled pilot in such a way as to make direct flight control changes to the aircraft""s flight path without abrupt flight dynamics resulting from the direct flight control change that was initiated by the skilled pilot in the autopilots returning to the original flight path or the new flight path.
Special emphasis is placed here in this application that both of the aforementioned prior art devices of U.S. Pat. Nos. 4,642,774 and 5,255,880 require that xe2x80x9conlyxe2x80x9d a skilled pilot, versed in the manual flight operations of the particular aircraft flown and so equipped with said devices, should make changes in the positioning or repositioning of the pilot""s control stick or yolk in order to preclude the manual placement of the pilot""s control stick or yolk by an unskilled pilot in such a position and to such a degree as to cause a negative flight maneuver being initiated by the autopilot as a direct result of the unskilled pilot""s actions.
Described in U.S. Pat. No. 5,695,157 issued Dec. 9, 1997 to Coirier et al., is a device that assists in the piloting of an aircraft or helicopter by a skilled pilot only during a landing in bad weather and only works in conjunction with a ground based radio-electric ILS (glide slope) system. The device provides an audible alarm to the skilled pilot so that the skilled pilot can directly adjust the flight controls of the aircraft to assure a safer landing and advise the skilled pilot to xe2x80x9cgo aroundxe2x80x9d in order to avoid overshooting the runway""s safe touchdown zone. The device cannot be employed by a unskilled pilot safely but rather, is a device that aids a skilled pilot in landing an aircraft or helicopter in inclement weather.
U.S. Pat. No. 3,467,344 issued Sep. 16, 1969 to K. C. Kramer is a device for automatically offsetting the effects of wind shear on an aircraft during the landing of the aircraft when employed with automatic landing system utilizing ground based ILS (glide slope) telemetry. The device aids a pilot in limiting the very sudden effects of wind shear on an aircraft""s roll, pitch or yaw while landing by sensing when the aircraft has exceeded a safe roll, pitch or yaw limit as a result of a sudden wind shear. The effect of the invention is such that when a sudden wind shear negatively affects the aircraft while close to the ground during landings an automatic and near instantaneous adjustment by the device of the aircraft""s flight controls are effected to offset the affects of wind shear on the aircraft at a much greater response time than a skilled pilot could respond to. The device is only applicable to landing an aircraft and works in conjunction with ground based radio-electric ILS (glide slope) systems. The device cannot be employed to totally fly an aircraft by an unskilled pilot, but rather, can only be employed by a skilled pilot in assisting the skilled pilot in landing an aircraft in the event of wind shear during a land based ILS glide slope assisted landing.
Describe in U.S. Pat. No. 3,386,689 issued Jun. 4, 1968 to Robert H. Parker et al. is a device for overriding autopilot control of large transport aircraft subsequently allowing a skilled pilot to maneuver the aircraft in the traditional manner of prior art of flying aircraft without autopilots in accordance to the magnitude and linear displacement of the pilot""s control stick or yoke to effect flight changes in the aircraft and subsequently allowing the autopilot to assume the new heading upon the pilot releasing the aircraft""s control stick or yoke to a detent position. The invention allows only a skilled pilot to safely effect autopilot heading changes by means of manual changes in the aircraft""s conventional flight controls. The device does not allow for the autopilot heading changes to be effected safely by an unskilled pilot.
In U.S. Pat. No. 5,493,497 issued Feb. 20, 1996 to Henning Buus is a triple redundant fly by wire flight control system extremely similar to the quad redundant fly by wire flight control system described in Military Standard 1553, (MIL-STD-1553), developed in the 1970""s and employed in modern aircraft such as the Lockheed Martin F-16 Fighter, and the Northrop Grumman B-2 Bomber. The invention is a flight control system however, and is not an autopilot but does employ an air data computer and additional features of such prior art.
As the system is fly by wire, one of the features of U.S. Pat. No. 5,493,497 is similar to MIL-STD-1553 in that the system affords the pilot a xe2x80x9cfeelxe2x80x9d for flying an aircraft both physically and visually whether a skilled pilot is flying the aircraft or it is being flown autonomously by the flight computer in autopilot mode. Another feature of the system is that it allows for controlled flight of aerodynamically unstable aircraft, designs such as the F-16 Fighter and the B-2 bomber. Also, like the prior art the system allows the pilot to override autonomous mode to effect flight control changes.
Being that U.S. Pat. No. 5,493,497 is a fly by wire system and thus xe2x80x9celectronicxe2x80x9d, and in order to provide a xe2x80x9cfeelxe2x80x9d for flying, the system, also like the prior art, makes changes to an aircraft""s flight control surfaces that are xe2x80x9cdirectly proportionatexe2x80x9d to the displacement of the pilot""s control stick and rudder pedals which requires pilot skill to preclude negative flight maneuvers. As the pilot""s controls effect proportionate linear changes in terms of magnitude in the flight controls the magnitude component of the pilots control over the aircraft flown by the system would, therefore, preclude safe operation of an aircraft employing the system by an unskilled pilot.
The invention relates to the fields of aircraft in general, and to integrated flight control systems employing autopilots specifically, when employed in combinations thereof and embodied therein in an airplane, helicopter, or unmanned aircraft having flight control systems employing congruent combinations of industry standard gyroscopic, electronic, mechanical, electro-mechanical and aerodynamic means of maintaining airborne platform stability during flight; and, whereupon such congruent systems combine to provide for safe aerodynamic control and steering of an aircraft in 3 axis by a skilled pilot.
It is the object of the invention to improve overall flight safety by providing a means capable of significantly reducing a skilled pilot""s work load and/or eliminating or supplanting the piloting skills normally required to fly any manned or unmanned helicopter or aircraft equipped with an autopilot employing a digital flight control system.
The invention has specific commercial and military applications in the unmanned aerial vehicle (UAV) market as well as the manned aircraft market. As of the date of this application, Federal Aviation Administration (FAA) policy regarding commercial use of UAVs is very restricted. These restrictions are predicated on concerns of safety regarding the design of such UAVs and their use by the general public.
With respect to safe operation of a UAV in a commercial application the FAA requires that certain safe operational attributes of a UAV design be demonstrated before authorization for it""s use in a commercial/civil application is granted. Four of these FAA concerns are as follows:
(1)xe2x80x94Pilot situational awareness
(2)xe2x80x94Controllability and stability of the platform
(3)xe2x80x94Interruption of the control data link (lost link)
(4)xe2x80x94Ease and safety of operation
The invention disclosed in this application addresses the aforementioned four FAA safety concerns inclusively.
In the case of unmanned aircraft applications the SFD, depicted by the block diagram of FIG. 2, may be employed in any UAV application equipped with an autopilot having a digital flight control system. The SFD can afford any UAV aircraft so equipped to address the aforesaid FAA safety requirements.
In the case of manned aircraft applications the SFD can significantly reduce a skilled pilots"" workload in piloting operations where the aircraft piloted is likewise so equipped with an autopilot having a digital flight control system.
Aviation and aerospace history teaches that it is well know in the art that aircraft, and helicopters whether manned or unmanned can only be safely controlled and operated in one of two ways. One way as history and the prior art points out is that for any given aircraft or helicopter to be flown safely without assistance of the prior art is that it must be flown xe2x80x9chands onxe2x80x9d the pilot""s flight controls by a trained pilot skilled in flying the particular aircraft flown by the pilot. Given the state of the art of the prior art a second way to safely fly an aircraft is autonomously by means of an autopilot. However, this latter means still requires a skilled pilot in order to make changes in the autopilot""s way point repertoire in order for the autopilot to be an effective piloting tool in flight. It, therefore, stands to reason as the prior art teaches that it is not obvious to those skilled in the art that a pilot""s xe2x80x9cskillxe2x80x9d can be eliminated in the application of the prior art.
The SFD device is devised to address the complexities of flying the HOVTOL UAV of U.S. Pat. No. 5,890,441 and also to address FAA concerns for allowing UAV technology to be employed by the general public. Additionally, the SFD device needed to address the type of end user of the HOVTOL invention in user applications by such personnel as firemen, police officers, farmers, merchant seamen and the like. In order for the HOVTOL to be commercially viable in light of the crash rate of UAV""s employing prior art techniques i.e. direct RC control or autonomous operation by xe2x80x9cskilledxe2x80x9d RC pilots and in knowing the personnel who will operate the HOVTOL UAV will most likely not be pilots a novel solution was needed hence the SFD device.
To effect what was needed in order to safely fly the HOVTOL UAV of U.S. Pat. No. 5,890,441 by commercial users who would typically not have RC piloting skills a requirement is thus established that the HOVTOL invention would have to be flown autonomously by an autopilot at all times. Secondly, changes in the HOVTOL""s autopilot program am for heading, speed, altitude, and function (i.e. mode of landing, taking off, hovering etc.) would have to be effected by personnel not skilled in flying RC aircraft. Therefore, such changes should be effected by the SFD device of FIG. 1 and as employed in FIG. 2 which is a simplified representation of the flight control system of the HOVTOL UAV of FIG. 3 cited in U.S. Pat. No. 5,890,441.
In general the unskilled HOVTOL pilot would make changes to the HOVTOL""s direction, speed, altitude and mode or function by simple, discreet , non-linear and non-proportional manipulations of the joy stick FIG. 2, 78 and one or more of a bank of 7 function switches FIG. 2, 77 installed in the SFD 58 of FIGS. 1 and 2. The SFD circuit FIG. 2 thus interpreting the pilot""s desired heading, speed, altitude and function thus changes the program set of the HOVTOL""s autopilot""s digital flight control software (ADFCS) of FIGS. 1 and 2 of the HOVTOL""s autopilot FIGS. 1 and 254 on board the aircraft of FIG. 3 by means of an electrical interface FIG. 183 from the SFD 58 to the pilot""s ground control station (GCS) shown in FIG. 1, 57 and subsequently relayed by a radio telemetry means FIG. 182 via the GCS""s and the UAV""s telemetry transceivers FIG. 155. The HOVTOL UAV""s autopilot 54 would thus articulate congruently; according to the HOVTOL""s flight laws stored in the HOVTOL""s autopilot 54; the appropriate air control surface servos FIG. 160 which thus articulate the various air control surfaces of FIG. 1: 2, 3, 4, 10, 11, 12, 13, and 17; and the HOVTOL""s horizontal propulsion propellers FIG. 1: 14, and 15; and the HOVTOL""s vertical lifting fans, and engine(s) (not shown) to effect safe flight maneuvers.